The Hypothesis ProcessEXPLAINING THE HYPOTHESIS TEST PROCESS

PRESENTED BY TEAM A: ROGER GOMEZ, CHRISTIAN GLORIA, AND DUSTIN BUJANDA

The Problem

The claim by a weight loss company is that, on average, the client will lose 10

pounds over the first two weeks. 50 people who joined the program were

sampled. Their weight loss is 9 pounds with a standard deviation of 2.8

pounds. Can we conclude, at the .05 level (95% confident), that a person will

lose less than 10 pounds.

List Important Data = Mean from Claim, Prediction, Null Hypothesis = Sample Mean (Actual findings from study, research, analysis. = Level of Significance (.05, .01, .10); /2 S = Standard Deviation (Find the Variance, take the

Draw “Comparison Distribution”

100

0.05 95%

Cutoff Z-score = -1.65 Z-Table

.05/1= .05

Calculate or Pick a Critical Value1. Level of Significance Chosen by Researcher or Client.

2. Most Common Are: .05 (95% Confident), .01, .10

3. The Formula for Critical Value is: Zα/2

4. Will appear in problem as …a. Can we conclude, at the .05 level, that…

b. At the 5% level of significance is the mean …

c. At the .10 level of significance, has the selling…

.05/2= .025

95%

Z-Table

Used for finding Confidence Interval: Zα/2 X

Calculate Null & Alternate Hypothesis

Always begin by solving the Alternate Hypothesis first simply by asking “What is the Alternate Hypothesis asking?” In our example case, “Is the mean

So,

Alternate Hypothesis: The true or actual mean of the population under analysis.

H1: 10

Null Hypothesis: the hypothesized mean of the population under analysis.

Ho:

Decision Rule & Calculate Sample Z Score

Reject Ho if Z < -1 .645

Calculate Z:

Yes, -2.53 is less than -1.65 T-Score Exa

mple

Write Report Conclusion: We reject the Null Hypothesis (Ho) and conclude the mean weight loss is less than 10 lbs.

Questions

References

Statistics for Psychology, Fifth Edition, by Arthur Aron, Elaine N. Aron, and Elliot J. Coups. Published by Prentice Hall. Copyright © 2009 by Pearson Education, Inc.

Z-Table

Back to Slide 5

Z-Table for Problem

Back to Slide 4

Confidence Interval

.781.9695% 9.788.22

Back to Slide 5

T-Score

Back to Slide 7

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